An ownship vehicle may include a collision avoidance and/or situational awareness system for alerting its operator to a potential collision with another vehicle by predicting a maneuver based on passive surveillance of signals transmitted from the other vehicle. The system may determine the position of the other vehicle, as well as characteristics such as the velocity and direction of travel. Based on these characteristics, the system may create a protection volume (e.g., a safety envelope) around the ownship vehicle and/or the other vehicle for the purpose of predicting the likelihood of a collision between the two vehicles. The system may also predict a collision between the ownship vehicle and the other vehicles.